Tenoscopic‐assisted treatment of a solitary caudodistal tibial osteochondroma

Abstract

Solitary osteochondromas are a relatively infrequent cause of lameness in the horse, most commonly occurring in the caudal distal radial metaphysis, with sparse reports in other locations. Their presence adjacent to a synovial sheath frequently results in intra-thecal tendinous laceration and resultant synovial effusion. Surgical excision in combination with arthroscopic debridement of the tendinous pathology offers the best prognosis for soundness. This report details the successful treatment of a caudodistal tibial osteochondroma using a combination of open surgical excision and tarsal sheath tenoscopy.

Computed tomographic (CT) arthrogram contributes to the diagnosis of an osteochondroma of the distal calcaneus in a horse

“…There are no reported cases of malignant transformation of solitary osteochondromas in horses, and the histopathologic findings in this case suggested a benign process. Surgical removal via endoscopy is the current treatment of choice for appendicular lesions, with good outcomes presented in the literature in regards to return to athletic function and lack of recurrence (Welch et al 1990;Kenzora et al 1995;Chan et al 1996;Secombe and Anderson 2000;Wright and Minshall 2012;Russell et al 2017;Agass and Fraser 2018). For this case, a guarded prognosis for return to athletic function was suspected due to incomplete removal of the distal part of the osteochondroma and the degenerative joint disease present within the joint.…”

What is an osteochondroma?

“…Equine cases have a consistent pattern of presentation due to the more consistent lesion location. Most cases protrude into a tendon sheath, including the carpal sheath (Braake and Rijkenhuizen ; Wright and Minshall ), the tarsal sheath (Secombe and Anderson ; Agass and Fraser ) and the sheath of the extensor carpi radialis tendon (Russell et al . ).…”

“…The case report by Agass and Fraser in this issue () describes the diagnosis and successful surgical treatment of an osteochondroma in a 3‐year‐old Polo pony mare. The unusual features of this case include the uncommon location of the osteochondroma within the caudal distal metaphysis of the tibia and the requirement of an extrathecal approach to enable its removal.…”

“…). Histopathological findings in the case reported by Agass and Fraser () were typical of an osteochondroma in that the tissue was covered in a smooth layer of cartilage, with evidence of endochondral ossification.…”

“…Although osteochondromas are usually surgically accessible via the synovial lined tendon sheath into which they protrude, they originate in an extrasynovial location and when examined tenoscopically are observed to be overlaid by, or protrude through, the synovium (Secombe and Anderson ; Wright and Minshall ). This may explain why the base of the large osteochondroma treated by Agass and Fraser () was more readily accessed by an extrathecal approach. I have encountered one case of an osteochondroma located in an entirely extrathecal location on the caudolateral aspect of the distal metaphysis of the radius.…”